Category: CGA

This is what happens when you don't resist the urge to poke at old games with sharp sticks.  You get 1 (one) ancient Asteroids clone for the IBM, a whole bunch of variations on a positively bonkers video mode, and a complimentary detour on the trail of a non-PC version, because that's how we roll.

We've seen how the MC6845 CRTC can produce unintended, 'phantom' vertical sync pulses if R7 is re­written during active display time.  How about the HD6845?  Well, Hitachi's 6845 variant appears to be more sensitive, and will glitch in even more cases than its Motorola counterpart.

A dive into an obscure hardware glitch in the 6845 CRTC chip, which has to do with register rewriting, and only seems to really have a noticeable effect on IBM CGA boards (so far).  Let's see what it is, why it occurs, and how to avoid it.  There's bonus fractals, too!

CGA can output 16 digital RGBI colors, and there's a well-known standard palette which translates them to (s)RGB values - but that palette isn't a very good approximation of the colors you actually get on IBM's original CGA monitor.  Why is that, and can we do better?

Believe it or not, it's possible to transport ancient CRTs across continents, even with today's shipping services pulling out all the stops on incompetence.  Here's how an IBM Color Display was packed, shipped, and lived to tell the tale.

Using a TV set as a CGA display device has its issues, especially horizontal centering and color in 80-column text mode.  These utilities should help.  There's a bootable version too, so you can throw it at your favorite booter games.

A few techniques derived by trial-and-error, and some obvious pitfalls to avoid.  May prove useful to you other amateur CRT photographers out there.

A fully-equipped IBM 5160 braves the rigors of international shipping and gets here in one piece (just barely).  As will be pictorially demonstrated, 30+ years after leaving the factory, this steel warrior is still one tough SOB.

After giving Keen 4's CGA version a 16-color composite overhaul, I figured I'd have a go at the next episode.  More custom code and graphics for the artifact-color aficionado.

This game is a pretty impressive piece of CGA programming, but there's one thing it doesn't do: exploit NTSC quirks to get 16 colors on a TV/composite monitor, instead of the familiar 4.  Here's how you can change that with a patch and a custom set of converted graphics.

Another installment on CGA display tricks - covering the final version of 8088 MPH, determining the model of your CGA card in wetware, the extended 1024-color palettes supported by both models, and some artistic considerations.

Can you take the original IBM PC color graphics board, and force it to display 32 times as many colors as it's officially capable of?  Believe it, comrade!  Here's the in-depth write-up on how we did that in the 8088 MPH demo, complete with illustrations.